In Voice-over-IP (VoIP) communication systems, such as in a Wi-Fi network for example, a jitter buffer is a buffer in a receiver of a user device where voice packets can be received, stored and sent to the voice processor in evenly spaced intervals. Jitter is a variation in packet arrival time, which can occur because of nature of Wi-Fi communication networks, which have inherent intermittent delays. The jitter buffer purposely delays the received packets in order to minimize delay variations so that a user of the device experiences voice communications with very little latency. However, there is a problem with jitter buffers in battery-operated devices, wherein to overcome the intermittent delay issues, it has been necessary for a user device to continually communicate with an access point to maintain a stream of voice packets, which uses significant transmitter, and receiver, power resources. Although this is required when a battery-powered devices is transmitting voice packets, it can be a problem when the device is not transmitting, and has sufficient packets in its input buffer.
A solution to the problem has been to use power save operating modes. One of these modes allows legacy user devices to go into a sleep mode and wake-up periodically to listen to an access point's beacon. The AP buffers packets for a particular device if the device is in sleep mode, and indicates the availability of pending packets in the beacon frame. The user device, when it wakes up, checks the beacon to see if there are pending packets for it. If not, the user device goes back to sleep. Otherwise, the user device polls the AP to retrieve the packets. However, this solution still requires a user device to regularly wake up quite often, even if there are no packets waiting for it, which wastes power.
Another solution is to use scheduled or unscheduled Automatic Power Save Delivery, wherein a user device needs to send a trigger frame to the AP, to cause the AP to deliver packets to the user device. The user device will then receive and acknowledge voice packets sent from the AP until the end of a service period. However, in this solution the user device will continue to send trigger frames to the AP even if its jitter buffer is full, which wastes power.
Accordingly, there is a need for jitter buffer management for improved power savings in a wireless communication device.
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